Thisbookcontainsthepostproceedingsofthe6thEuropeanWorkshoponPublic Key Services, Applications and Infrastructures, which was held at the CNR Research Area in Pisa, Italy, in September 2009. The EuroPKI workshop series focuses on all research and practice aspects of public key infrastructures, services and applications, and welcomes original research papers and excellent survey contributions from academia, government, and industry. Previous events of the series were held in: Samos, Greece (2004); Kent, UK (2005); Turin, Italy, (2006); Palma de Mallorca, Spain, (2007); and Trondheim, Norway (2008). From the original focus on public key infrastructures, EuroPKI interests - panded to include advanced cryptographic techniques, applications and (more generally) services. The Workshops brings together researchersfrom the cryp- graphiccommunity as well as fromthe applied security community, as witnessed by the interesting program. Indeed, this volume holds 18 refereed papers and the presentation paper by the invited speaker, Alexander Dent. In response to the EuroPKI 2009 call for papers, a total of 40 submissions were received. All submissions underwent a thorough blind review by at least three ProgramCommittee members, resulting in careful selection and revision of the accepted papers. After the conference, the papers were revised and improved by the authors before inclusion in this volume.